1. Field of the Invention
This invention relates to the field of portable electronic apparatus such as mobile telephones, particularly but not exclusively to a housing assembly including a clip arrangement for securely attaching a display window to a mobile phone cover.
2. Description of Related Art
The majority of conventional mobile telephones have a liquid crystal display for displaying information relating to mobile phone operation, such as the telephone number being dialled, address lists, phone settings and so on. The display is viewed through a protective plastic window, which forms part of the front housing of the phone. FIGS. 1a and 1b illustrate several conventional techniques for assembling parts of a housing. For example, referring to FIG. 1a, the front housing 1 of a mobile telephone includes a cover portion 2 and a window panel 3, comprising a clear window 4 and a frame 5. The window panel 3 is held in the cover portion 2 by layers of adhesive 6, but this often fails at the higher operational temperatures which may result from prolonged phone use. Tabs 7 can be used to aid retention but often snap off if the phone is accidentally dropped. Furthermore, tabs can only be used at one end of the window panel 3 to allow assembly, so that the opposite end of the panel 3 will peel away from the cover portion 2 and ultimately drop out if the adhesive 6 fails.
Referring to FIG. 1b, a further known type of clipping arrangement comprises a deformable clip 8 in one housing part 9 which rides over a lip 10a of a retaining member 10 in the mating housing part 11 and clips behind the retaining member 10 to hold the respective housing parts 9, 11 together. Such clips are generally required to be long and thin in section to achieve the appropriate degree of deformation, as a result of which they snap off easily. In addition, the length of the clip requires significant clearance in the mating part 11, which is not practical in small assemblies.
Clip arrangements are also known in which additional components such as metal spring arrangements are used to provide clip retaining features in one part of the housing. Such solutions increase manufacturing complexity and therefore the cost per unit manufactured.